Skip to content
Free Local Pickup ● Ship to Your Hometown Store
Pro & Contractor Accounts ● Apply for Net Terms
100,000+ Products ● Trusted Authentic Brands
FAQ Shipping & Returns Order Lookup Contact Account
SPAX PowerLags 5/16 in. in. X 8 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 8 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 8 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 8 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 8 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 8 in. L T-40 Washer Head Serrated Structural Screws

SPAX PowerLags 5/16 in. in. X 8 in. L T-40 Washer Head Serrated Structural Screws

Made in America

Support American manufacturers + independent hardware retailers in one purchase.

One fastener does the job of multiple bolts, with a self-tapping thread that skips the pre-drilling step.
Spax MPN 4581820802035 In Stock & Ready to Ship
Local Price Check i Local stores may price this as low as $89.99. Our online price is $99.99.
$99.99
Includes free shipping on orders over $75 · $8.99 standard below
Delivery in as little as 1–4 business days Order within — for same-day shipping
Shop Local · Support Independent

Every order helps keep your local hardware store on the corner.

Why we built NHG
You might find it for less locally. Independent retailers often offer competitive pricing — some products are even cheaper in-store than online.
Real expert advice — not search results. Independent hardware staff know their inventory and the local conditions you're working in.
Keep the neighborhood working. Every dollar spent at an independent retailer returns roughly 3x more to your local economy than at a national chain.

About Product Overview

SPAX PowerLags are built for wood-to-wood connections that need to hold, whether that's timber framing, deck ledger boards, or heavy post-to-beam work. At 8 inches long and 5/16 inch in diameter, these Grade 5 carbon steel screws replace multiple structural bolts or lag screws in a single fastener, cutting install time without cutting strength.

The serrated thread bites into wood fast and self-taps, so there's no need to pre-drill in most applications. A T-40 washer head spreads clamping force over a wider area, and the included driver bit means you're ready to drive as soon as you open the box. The high corrosion-resistant black finish holds up whether the screws end up buried in an exterior deck frame or inside a wall.

  • Length: 8 in. / Diameter: 5/16 in.
  • Grade 5 carbon steel construction
  • Serrated, self-tapping thread
  • T-40 washer head with included driver bit
  • High corrosion-resistant black finish, indoor/outdoor rated
  • Boxed, 50 screws per package, made in USA

The Details Specifications

Brand Spax
UPC 712216023161
Case Pack Quantity 2 per case
Retail Unit Quantity 1
Dimensions (L × W × H) 4 × 10 × 3
Weight 5 lbs
Country of Origin USA
Safety Data Sheet (SDS) Manufacturer documentation · opens in new tab

Ask our counter. Or theirs.

Most hardware stores can do more than you think. If we can't help you, the folks down the street probably can — just ask at the counter.

What we offer
Free Local Pickup Ship to your hometown store
Pro & Gov Accounts Net terms · tax-exempt
Ships Nationwide From our distribution network
Independent Network Real hardware stores
$0.68 of every dollar spent at a local independent business stays in the community. At a national chain, it's about fifteen cents. Civic Economics, multi-city retail studies
Their Counter
Try local first · we'll wait

The stores we send you to are local and independently run — often for generations, the kind of place where someone behind the counter knows the regulars. We don't own them. We just think they deserve the foot traffic. They can put most of what we sell on their next truck. Ask there before you check out here.

Find a local store →
Mon–Fri 6–5 PST
Independent hardware retailer? Join the network →
About our directory. National Hardware Group is an independent retailer and directory. The local stores we list and link to are separately owned and operated — we have no ownership stake in any of them, and most pay us nothing to be included. That includes plenty of stores flying a co-op banner that people don't realize are locally owned and run, not operated by a corporation. Store owners can choose to upgrade their listing for an enhanced presence or pickup features, but the base directory is free, and inclusion is never a paid endorsement.

Compare products

{"one"=>"Select 2 or 3 items to compare", "other"=>"{{ count }} of 3 items selected"}

Select first item to compare

Select second item to compare

Select third item to compare

Compare